That's according to retired US Navy officer Robert Ballard, who successfully led an underwater expedition to locate the sunken ship in 1985.

Speaking to CNN and CBS about the now-declassified events, Ballard revealed that his expedition was part of a covert US military operation.

Ballard was tasked with finding the USS Thresh and USS Scorpion, two nuclear subs that sank in the 1960s.

And the hunt for the Titanic was the perfect front: "They did not want the world to know that, so I had to have a cover story," he explained.

It wasn't a complete conspiracy, however.

Ballard did actually want to find the Titanic, but couldn't get funding for the expensive expedition.

The US Navy eventually offered to cough up the money – and it came with one big condition.

Ballard would have to track down the submarines before the Russians – then a key rival in the ongoing Cold War – could find them.

"We knew where the subs were," Ballard revealed.

"What they wanted me to do was go back and not have the Russians follow me, because we were also interested in the nuclear weapons that were on the Scorpion, and also what the nuclear reactors [were] doing to the environment."

He said that the mission was "very top secret", and was hidden from the public.

"I said: 'Well, let's tell the world I am going after the Titanic'."

Unfortunately for Ballard, the covert part of the mission took longer than expected.

After finding the Scorpion, he had just 12 days left to find the Titanic.

But his search for the nuclear subs had given him some helpful experience.

"I learned something from mapping the Scorpion that taught me how to find the Titanic: look for its trail of debris."

He eventually found the Titanic, and had four days left over to film the wreckage – because the ship was due to be rented out by someone else.

"People had taken 60 days and not found it. I did it in eight," he said.

Ballard recalls being immediately excited by the find, but the mood quickly turned somber.

"We realized we were dancing on someone's grave, and we were embarrassed," he said.

"The mood, it was like someone took a wall switch and went click.

"And we became sober, calm, respectful, and we made a promise to never take anything from that ship, and to treat it with great respect."